Human sexual orientation has been a controversy with a high tendency for debate. Lesbians, gays, supporters, and their friends are in a heated dispute about the origins of sexual orientation. There are many possibilities, spanning from personal lifestyle choices, environmental factors, to genetic heredity.

In the past few years it has become increasingly popular to examine homosexuals, in hopes of determining the basis for a lifestyle involving same sex relationships. Henry Havelock Ellis first addressed inquiries on the basis of homosexuality over a century ago. Ellis stated that people engaging in sexual practices deviating from the regular format should be accepted by society, and laws against this group of people should be put aside, due to the biological differences of each persons makeup (Hyde & DeLamater, 1997). Most of the recent discussions and studies on homosexuality with a genetic influence have begun in the past decade.

Many researchers of this decade have been involved in the discovery of a "gay gene", but none as much as the infamous Dean Hamer (Pool, 1997). Hamer studied under molecular biology and psychology, so there is

The Hamer study supported a theory that there may be a possibility of traits passed down through the genes of mothers that determine a linkage between genetics and human sexual orientation. The fact still remains that much more testing is in order to fully determine the sequence of the human genome in general, not to mention specific genes relating to one specific category, such as human sexual orientation.

Hamer and colleagues performed an X-chromosome linkage on several pairs of homosexual brothers. The reason for using brothers is the obvious relationship of each individual DNA structure, and the ability to recognize even slight differences on each genome. Mistakes in comparing genotypes of brothers are uncommon. The mothers and siblings, if any were available, also had DNA samples prepped for examination, to view similarities of markers that run up and down the X-chromosome. Again to narrow the search for the specific gene, only the brothers who had the same X allele from their mothers (which was the majority) were continually looked at (Hamer,Hu,Magnuson,&Pattatucci, 1993).

At the end of each strand of male DNA there is a specific X-chromosome that is obtained from the mother of the individual and a Y-chromosome which comes only from the father. While looking at the similarities between father, son, and homosexuality, it was determined by the team that if homosexuality was a specific genetic trait, it most probably was passed through the mother of the subject. This in turn determines that if the X-chromosome is responsible for passing the trait of homosexuality then related gay men should have a specific gene or chromosome marker which indicates their sexual orientation (Hamer,Hu,Magnuson,&Pattatucci, 1993).

Another study has been underway for some time, dealing with the genetic aspects of sexual orientation in fruit flies. This does not directly pertain to the human portion of this study, but it may demonstrate that a sexually defining gene is a possibility. Work accomplished at Stanford University, along with many other universities, have discovered a gene that inhibits the male fruit fly from distingui

Some common words found in the essay are:
X-chromosome Pool, Stanford University, Dean Hamer, X-chromosome Xq28, Orientation Human, Hamer Pool, Havelock Ellis, Hyde DeLamater, sexual orientation, human sexual orientation, human sexual, environmental factors, gay gene, genetics human sexual, hamerhumagnuson&pattatucci 1993, specific gene, fruit flies, genetics human, shared environmental, shared environmental factors, male fruit fly, link genetics,
Approximate Word count = 1449
Approximate Pages = 6 (250 words per page double spaced)